I believe that Sahalee had its three 9-hole loops built from the beginning. For members' regular play, they alternate the 9s for a daily 18 hole usage. For tournaments, they regularly use the same two 9s (North and South, I believe - but am not 100% sure).
Of course, my main criticism of Sahalee is that so many of the holes are alike that few distinguish themselves - on all three 9s. Just a bunch of long, narrow, tree-lined holes